Circuit breaker



March 11, 1952 H. R. LINDBECK CIRCUIT BREAKER Filed May 29, 1946 lNl/ENTOR HOWARD R. LIN DBECK 1. Mad/0a Patented Mar. 11, 1952 CIRCUIT BREAKER Howard B. Lindbeck, Beloit, Wis., assignor to Fairbanks, Morse & Ce., Chicago,- 111., a corporation of Illinois Application May 29, 1946, Serial No. 672,951

1 Claim. 1

This invention relates to circuit breakers of a character suitable for use in ignition systems of internal combustion engines, and has particular reference to improvements in the construction and arrangement of operating parts of a circuit breaker, affording acircuit breaker which is particularly suitable for use in ignition systems of high speed engines.

The principal object of the present invention is to provide an improved circuit breaker for the purpose indicated, embodying a cam follower member of improved form and construction, for actuating the movable breaker contact, and including a provision for stabilizing operation of the cam follower member particularly during high speed operation of the breaker.

Other objects and advantages afforded by the present improvements will appear from the following description of a presently preferred embodiment of the invention as such is illustrated in the accompanying drawing, wherein:

Fig. 1 is a view in plan elevation of a circuit breaker structure wherein is embodied the present improvements;

Fig. 2 is a an enlarged perspective view of the presently improved cam follower member, and

Fig. 3 is an enlarged sectional view of a portion of the breaker assembly, as taken from the line 3--3 in Fig. 1.

With reference now to the drawing and in particular to Fig. 1, the circuit breaker includes a support or base plate In through the central portion of which extends a shaft II, the shaft having suitably secured thereon a circuit breaker operating cam I 2. Although not here illustrated, the shaft II is rotated in timed relation with the engine crankshaft through any suitable operating connections with a crankshaft driven part, as for example, the engine camshaft. On plate In near the lower margin thereof is an outstanding pivot element or stud I4, and pivoted at one end on the stud is a bracket I5 which is adjustably fixed to plate If! as by screws I6 through bracket slots I8. The free end of bracket I5 is provided with an upstanding flange or lug I9, to which is secured as by a screw 20, one end of a flexible member or leaf spring 22 of conducting material, the spring member supporting at a point thereon intermediate its ends, the movable contact 23 of the circuit breaker assembly. Operatively associated with the movable contact 23 is a fixed contact 24, the latter being supported in a position opposite to contact 23, by a further upstanding flange or lug 26 on the bracket I5. The member 22 carrying movable contact 23, is

ill

here insulated from the flange I9 and bracket I 5 by washer or bushing elements 21 and 28 each of suitable insulating material, at the screw support 20, these insulating elements being adapted to insulate the screw 26 from bracket I 9. A conductor element 30 of flat ribbon character, connects spring member 22 with a circuit connection post provided by a screw 3I carried by an upstanding flange or lug 32 on bracket I 5, the screw 3I being insulated from the flange by suitable insulating washers or bushings 34 and 35. Connected to post 3I is a lead or conductor 36 which may extend for connection in the primary circuit of the ignition system '(not shown). The other side of the primary circuit extends to the fixed contact 24 through the usual ground cir cuit, as is indicated by the ground connection 3! to contact 24.

For actuation of the movable contact 23 through its spring support 22, there is here interposed between the cam I2 and the free end 38 of spring member 22, the operating end 39 of a cam follower member 40. Member 40 comprises a single arm of relatively short extent, terminating opposite the end 39 in a hub 42 adapted to seat over the stud I4 whereby to afford a pivotal support of the member, the member being retained in its pivotal support on stud I4 by a washer and lock pin assembly indicated at 43. Member 40 at its end 39, is provided with a lateral projection 44 adapted for follower engagement with cam I2, and on its opposite side is provided with a lateral projection or nose element 46 to engage the free end 38 of spring member 22, the nose 46 as appears, being inclined forwardly of the arm. As appears in Fig. 1, the arrangement is such that when the follower is in engagement with a high point of cam I2, spring member 22 is lifted or displaced by the nose 46 such as to disengage movable contact 23 from the fixed contact 24. When the follower is on a low point of the cam, contacts 23 and 24 will be in engagement.

The follower member 40 according to the present improvements, is formed as a unitary structure from a suitable rigid insulating material such as Formica, the member being relatively small and exceedingly light in weight such as.

to facilitate quick pivotal response thereof to cam movement. Moreover, the leaf spring 22 supporting the movable contact 23. is selected in respect to its spring characteristic, such as to afford a positive bias of member 40 in the direction to maintain the projection 44 of the follower member in substantially constant contact with the cam l2. However, it has been found in the operation of the circuit breaker at high speeds, that in spite of the follower loading by the leaf spring 22, there is a tendency for the light follower member 40 to be displaced or bounced away from the cam. Accordingly, included in the present improvements is an effective provision for preventing such displacement or bouncing of the member 40 during high speed operation of the breaker.

As will appear from the several figures, the intermediate or stem portion 50 of member 40 is provided with a circular recess in the side thereof opposed to the bracket flange 32. A coiled compression spring 52 of suitable capacity, has one end seated in the circular opening 5| and its opposite end sleeved over the free projecting end 54 of the post screw 3 l and in abutment with the screw securing nut 55. By this provision the spring 52 not only assists the leaf spring 22 in biasing the follower member 40 against the cam 82, but serves additionally, to prevent or damp out any tendency of the member 40 to bounce away from the cam under high speed operation. Thus the action of the member 40 is effectively stabilized such as to afford positive breaker operation at high speeds.

From the foregoing it will be now appreciated that the present improvements provide a circuit breaker structure of improved and relatively simple construction, and one which is especially suitable and effective for high speed operation, as in the ignition systems of high speed engines. Moreover and importantly to the present invention, the follower member 40 provides a one piece element which may be readily and easily manufactured, as by a stamping operation. It is to be noted in particular, that the member 40 does not carry or have secured thereto any part of the current carrying elements of the circuit breaker, which thus greatly simplifies manufacture of the member.

Having now described the invention in respect to a, presently preferred embodiment thereof, it will be understood that alterations or modifications in the parts and assembly relation thereof may be made without departing from the spirit and full intended scope of the invention as defined by the appended claim.

I claim:

In a circuit breaker for ignition systems of high speed engines, a, base member, a pivot ele ment on said member, a support plate pivotally adjustable relative to said base member about said pivot element as a pivotal axis, said support plate having three spaced upstanding flanges, an elongated flexible member of conducting material anchored on one of said flanges, extending alongside the second flange and terminatin in a free end adjacent the third flange, a contact point on said second flange, a contact point on said flexible member in engagement with the contact point on the second flange when said flexible member is in an unflexed position, a rotary cam, a rigid arm of insulating material pivoted at one end on said pivot element and having the other end interposed between and in constant engagement with said cam and the free end of said flexible member for flexing of said member to open and close said contacts in accordance with cam operation of said rigid arm, a circuit-connection post threadedly secured in said third flange having a shank portion extending therethrough, said rigid arm having a cylindrical recess in one side thereof in alignment with and confronting the portion of said circuit-connection post extending from said third flange, and a compression spring disposed in unsupported relation between said rigid arm and said third flange having one end encircling the extending portion of said connection post and the opposite end seated in the recess in said rigid arm, pivotal adjustment of said support plate relative to said base member eflecting bodily movement of the contact point on said second flange relative to said cam to increase or decrease the amount of opening of the contact points consequent to flexing of said flexible member.

HOWARD R. LINDBECK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Gibson May 16, 1944 

